Late Complications of Hematopoietic Stem Cell Transplantation
I. INTRODUCTION Stem cell transplantation of peripheral blood or bone marrow has evolved into an accepted treatment for a variety of life-threatening hematological, neoplastic, and immunological disorders. The numbers and types of transplants have increased as unrelated and mismatched related individuals are now used as alternative donors, as different sources of hematopoietic stem cells are employed, and as new disease indications are considered for transplantation (Kernan et al., 1993; Kurtzberg et al., 1996; Walters et al., 1996). As transplant outcomes improve with advances in supportive care, new treatment protocols are being developed to extend the application of stem cell transplantation to nonmalignant conditions such as sickle cell disease, thalassemia, and selected autoimmune disorders (Lucarelli et al., 1993; Sullivan and Furst, 1997). As shown in Fig. 1, there has been a steady increase in the number of transplant centers and an increasing number of longterm survivors (Armitage, 1994). Thousands of patients worldwide are currently alive more than 5 years following bone marrow transplantation and increasing attention is being directed to potential late complications (Sullivan et al., 1991).